Routing Policies and Firewall Filters
2. Default routing policies
In Junos, there are several default routing policies:
1. Import policy: Used to import routes into the routing table.
2. Export policy: Used to export routes from the routing table.
3. Trust policy: Used to set the default trust level for incoming routes.
4. Holddown policy: Used to ignore routes that are received and are less specific than a route that is already in the routing table.
5. Reject policy: Used to discard routes and prevent them from being installed in the routing table.
These default routing policies can be modified or replaced by custom policies to meet specific requirements.
3. Import and export policies
The import and export policies in Junos are used to control the exchange of routing information between the routing protocols and the routing table.
1. Import policy: The import policy is used to import routes from a routing protocol into the routing table. The policy specifies the conditions under which routes are imported and what actions are taken on the routes if the conditions are met.
2. Export policy: The export policy is used to export routes from the routing table to a routing protocol. The policy specifies the conditions under which routes are exported and what actions are taken on the routes if the conditions are met.
For example, you can use import and export policies to filter routes based on specific criteria such as AS number, route preference, or address prefix. By controlling the exchange of routing information, you can improve the stability and performance of the routing system.
